This is a multi-center, open-label, randomized, cross-over study to determine whether
steady-state, twice a day treatment with Cysteamine Bitartrate Delayed-release
Capsules(RP103) results in comparable depletion of white blood cell (WBC) cystine levels
compared to the existing four times a day cysteamine treatment. It will involve up to 20
clinic visits plus intermittent home use of the RP103. Most of these clinic visits occur in
clusters of 3-4 consecutive days. Eligible patients will be offered enrollment into a
long-term follow up study.